Scanning near-field optical microscopes have been developed in recent years to provide high-resolution optical imaging of micron and submicron-sized objects. (See, for example, E. Betzig and J. K. Trautman, Science, 257, (1992) 189.) Both near-field and confocal microscopes use small apertures to restrict light collected from an object to tightly confined regions in the object plane. The spatial resolution of these techniques is limited by the aperture size and the collection efficiency, which affect the signal to noise ratio. While both near-field and confocal microscopies have proven to be powerful imaging techniques, they typically require specialized small-aperture devices and elaborate aperture positioning and scanning instrumentation.